Relay



Oct. 30, 1951 A. w. FISCHER .2,573,000

RELAY Snnenfor Patented Oct. 301, 1951 RELAY Albert W. Fischer, Highland Park, Mich., as-

signor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Original application August 16, 1943, Serial No. 498,777. Divided and this application August 19, 1944, Serial No. 550,227

2 Claims. 1

vThis invention relates to relay means and more specifically to sensitive relay control means actuated by very small electrical currents.

There are many instances in which minute current flow is called upon to actuate control apparatus and this is usually accomplished through relay means of some sort. A majority of them are designed to be operated by substantial currents and would not be affected by very small ones. One example of an installation in which a very sensitive relay or galvanometer relay is used is in a temperature recording mechanism such as shown in my copending application Serial Number 498,777, iled August 16, 1943, subsequently abandoned, of which this is a division.

It is therefore an object of my invention to provide a very sensitive relay means.

It is a further object of my invention to prolvide a relay actuated by very small currents.

With these and other objects in View which will become apparent as the specication proceeds, the embodiments of my invention will be best understood by reference to the following specification and claims and the illustrations in the accompanying drawings, in which:

Figure l is a vertical section through the galvanometer relay.

AFigure 2 is a front elevation of the relay taken on line 2 2 of Figure l.

Figure 3 is a sectional view taken on line -S or Figure l.

Figure 4 is a rear elevation of the relay taken v on line t-d of Figure l.

The galvanometer relay indicated generally at it, consists of a substantially rectangular plate l92 having on its rear face a plurality of spaced magnetic core means indicated generally at i911 and l95 on opposite sides of the center. These core means are each formed of a cylindrical permanent magnetic member H and l9l which may be of Alnico or some similar material, and a central soft iron pole piece H99 and 20l respectively. In each of these core means there is provided a small circular air gap itt and 200 in which a continuous radial magnetic eld is present and in which are located two coils 202 and 206i. These coils are connected in series in the bridge circuit and are supported by thin circular hoops 20G- 203 which form the opposite ends of a transverse balanced bar 2 it which acts as the actuating member for the galvanometer.

The two coils 2m and 202, while being connected in series, are so wound that when current flows through them in one direction their magnetic ldelds will interact with the elds in the gaps so that one of the hoops will be attracted or pulled down into the air gap, while the other will be repulsed, thus giving a definite torque for operating purposes.

The central portion of the transverse member 2 l 0 is secured to a member 2 l2 which has a transverse opening 2|4 therethrough in which are secured small threaded screws 2 I6 to each of which are permanently connected one end of two thin metal strips 2| 8 and 220. The opposite end of the thin strip 2l8 is adjustably secured to an upright member 222 mounted on the insulating base |92, but terminating in a similar threaded screw member 224 which extends through an opening in the upright member 222, and has a pair of nuts on opposite sides of the member which can be threaded to different adjusted positions to stress the thin ribbon. In like manner, the thin strip 220 terminates in a threaded member 22B which is secured to a rotatable sleeve 228 mounted in an upright bracket 230 also carried by the member l92. This sleeve 228 has a small toothed gear 232 rigidly secured thereto by which the sleeve may be turned. Thus turning this one end of the at strip 220 will cause a torque in one direction or the other about this iiexible axis and cause the galvanometer movement to be biased in the turned direction. Mating with this gear 232 is a small gear 258 which is mounted on a shaft extending through the member l92 which can be turned by actuation of the zero adjustment of knob 20. Of course, the tension on these two thin strips 220 and 2l8 should be sumcient 'to support the galvanometer movement.

An opening 234 through the central portion of the insulating support l92 accommodates the movable contactors carried by the galvanorneter movement. These contactors consist of two spaced contact points 236 and 238 which may be oi platinum carried by the member 2l2 of the galvanometer movement and insulated from each other, the member 2 l2 being of insulating material. These two spaced contacts therefore assume a position between two adjustable contactors 242 and 244 carried by two bendable spring strips 2&6 and 2&3 having one end thereof rigidly secured to the member l92 and having their opposite ends interconnected by an insulating cross member 250 which in turn carries an armature member 252, in juxtaposition to a small electromagnet 254 mounted in an opening 256 likewise provided in the insulating member l92. Thus these spaced contacts 242 and 2M may be vibrated back and forth when alternating current is supplied to the small solenoid 255 and move over the surface of the ends of the mem- YVbers 233 and 238 and maintain the same clean.

be a good conducting engagement maintained between 242 and 244 and their associated contacts 236 and 233 respectively. Any current flowing in the circuit through the coils will therefore create forces tending to rotate the arm 2l0 around the axis ofthe strips 2I8 and 220 and cause closure of the associated contacts 242-236 or 244--233 depending upon the direction of flow and the amount of said current. Therefore it will be seen that I have provided a galvanometer movement in which torque is provided by two spaced coils, causing actuation in opposite directionsabout a flexible axis which provides a very sensitive movement, and means for keeping the contact clean and reducing surface resistance between the spaced adjustable points and the ends of the two movable contact means carried by the galvanometer movement. This construction also provides a zero adjustment by tensioning the flexible strip in one direction or the other about its axis by a manually adjustable means.

I claim:

1. In relay means, permanently magnetized means, pivotally movable means mounted in juxtaposition to the first named means having an adjustable bias about its axis. coil means mounted on said pivotal means on opposite sides of the pivot so wound and connected that the passage of current there through will cause a torque about the pivot in the same direction, a plurality of contact means carried` by the pivotal means, spaced adjustable contact means mounted for limited movement in the plane o the pivotal means engageable by the contact means carried by the pivotal means to provide switching means, and magnetic vibratory means for simultaneously vibrating the spaced adjustable contact means in its plane of movement relative to the pivoted contacts to maintain good contact surfaces.

2. In relay means, a base, movable contact means pivotally mounted on said base, bendable means having one end anchored to said base in juxtaposition to the pivotal means and deform- -able in'a radial plane with respect to the pivotal means, 'a plurality oi contact means adjustably mounted in spaced relation on said bendable means for engagement with the pivotally movable contact means at different positions of its rotative movement, magnetic vibratory means mounted on said base acacent the free end oi the bendable means to cause the latter to vibrate when the magnetic means is energized and thus to cause relative movement between the adjustable contact means mounted on said bendable means and the contact means on the pivotally mounted-means to cause a cleaning movement.

ALBERT W. FISCHER.

a ,-tENeEs crran The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 405,988 Burke June 25, 1889 1,062,380 Apple May 20, 1913 1,302,622 Apple et al May 6, 1919 1,460,173 Patten June 26, 1923 1,758,793 Hogan May 13, i930 1,870,840 Eames Aug. 9, 1932 1,939,427 Young Dec. l2, 1933 1,958,713 Reyman May 15, 1934 FOREIGN PATENTS Number Country Date 225,9867 Great Britain Dec. 18, 1924 229,259 Great Britain Apr. 23, 1925 

